Synchronet v3.19b-Win32 (install) has been released (Jan-2022).
You can donate to the Synchronet project using PayPal.
On FreeBSD, your options for running DOS doors are:
Trace: • JSexec • Security Level • Sysop • Domotron • Configuration • webv4 Configuration • Customization • Use Apache HTTP Server with Synchronet • How to Setup Docker on Ubuntu • Use DOS Doors with Synchronet on FreeBSD